“TRANSFORMATIVE HADRON BEAMLINES” WORKSHOP BROOKHAVEN NATIONAL LABORATORY

( UPTON, NEW YORK, USA)

FROM JULY 21 TO 23, 2014.

22 JUILLET 2014 | PAGE 1CEA | 10 AVRIL 2012

1 CEA Cadarache DEN-DTN 13108 Saint-Paul-lez-Durance France, 2 PSI Villigen; 3 ENEA Brasimone; 4 SCK-CEN Mol; 5 KIT ; 6 CNRS SubatechNantes; 7 JAEA Tokai; 8 DOE-LANL, 9 KAERI

MEGAPIE-TESTMEGAPIE-TEST

Departmentof Energy

Departmentof Energy

MEGAPIE: the world’s first high-power liquid metal spallation neutron source.

Ch. Latge 1 (CEA) France ( christian.latge@cea.fr ), M. Wohlmuther 2 (PSI) Switzerland (michael.wohlmuther@psi.ch) ,

Presented by Sylvie Leray (CEA) France

Y. Dai2, D. Gavillet 2, A. Gessi 3, A. Guertin 6, B. Hammer 2, S. Heinitz 2, J. Henry 1, M. Konstantinovic 4, S. Leray 1 , R. Lindau 5, C. Fazio5, S. Maloy 8, J. Neuhausen 2, S. Saito 7, K. Park 9, P. Roubin 1, K. Samec 2, D. Schumann 2, K. Thomsen 2, A. Türler 2, L. Zanini 2, W. Wagner 2

MEGAPIE EXPERIMENT

A key experiment in the ADS roadmap:

MEGAwatt PIlot Experiment (MEGAPIE) (1 MW) initiated in 1999 in order to design and build a liquid lead-bismuth spallation target, then to operate it into the Swiss spallation neutron facility SINQ at PSI .

It was to be equipped to provide the largest possible amount of

scientific & technical information without jeopardizing its safe operation.

SINQ @ PSI

Several main challenges for the MEGAPIE project : - to design a completely different concept of target in

the same geometry of the current spallation targets used at PSI. - to develop and integrate two main prototypical

systems : a specific heat removal system and an ele ctro magnetic pump system for the hot heavy liquid metal in a very limited volume.

- to design a 9Cr martensitic steel (T91) beam wind ow able to reach the assigned life duration.

- to license a LBE in relevant conditions- to operate a LBE target - to develop the decommissioning strategy and waste

management- to characterize LBE and structural material (PIE)

L

F

F

Beam Window380°C outside330°C inside

Downcomer3.75 l/s, 0.33 m/s

230-240°C

Bypass Tube0.25 l/s, 1m/s

230-240°C

Nozzle 1.2 m/sBeam Window 1 m/s

Guide Tube4 l/s, 0.33 m/s

380°C

Bypass Pump0.25 l/s, 0.2 m/s

230°C

Heat Exchanger4 l/s, 0.33 l/s/pin

0.46 m/s380-230°C inside

Main Pump4 l/s, 1.2 m/s

380°C

Heat Exchanger (Oil)10 i/s, 5.5 m/s

140-175°C inside

Design parameters:

p-beam energy: 575 MeVp-current: 1.74 mAHeat removal: 650 kWDesign pressure: 16/10 barDesign temp.: 400°CCover gas press: 3.2 bar Operation: 1 yearwith max 6000 mAhRadiation damage: 20-25 dpa

Dimensions

Length: 5.35 mWeight: 1.5 tLBE-Volume: 89 l

MEGAPIE TARGET

MEGAPIE PROJECT: DEVELOPMENT STRATEGIE

� Numerical simulation + experiments : from basic science to engineering tools for design & operation� Progressive validation of concept by basic studies, design calculations, integral tests� Operation with Post Test analysis and Post Irradiation Examination� Decommissioning and Waste management

Manufacturing

Integral tests

Operation

Dismantling

Quality Assurance

Licensing

Post TestAnalysis

PIE

Waste Management

Feedback for ADS

MEGAPIE PROJECT: MAIN STEPS

Requirements definition, organization: 1999-2000

Feasibility studies : 2000

Design studies: 2001-2004

Design support: 2001-2005

Manufacturing target & ancillary systems: 2004-2005

Integral Test: September to December 2005

Transfer to SINQ: January to Mai 2006

Irradiation : August 2006 to December 2006

Post Test Analysis: 2007-2009,Decommissioning: 2009-2012Sampling for PIE: 2011-2012PIE: 2013 & 2014Waste management: 2011-2013

FEEDBACK FROM TARGET MANUFACTURING

Relevant issue: development and assessment of suita ble joining and welding technologies of the selected materials for Target i n different geometries e.g. window, tubes of heat exchanger...

Joining and welding procedures qualified for variou s configurations, including preparation, welding and control.

Target manufacturing by ATEA company in Nantes (Fra nce)

FEEDBACK FROM INTEGRAL TESTS

Integral Test:

– to integrate the target and the ancillary systems,

– to carry out LBE filling and draining operations

– to check the operability of the main components of the target,

– to check and calibrate the instrumentation (mainly flow-meters)

– to determine the thermal hydraulics characteristics of the system,

– to simulate heat deposition (with a heater)

– to characterize the heat transfer and hydraulic beha vior at the window,

– to obtain the vital parameters for system control,

– to provide enough information for licensing the tar get for irradiation test,

– to gather technical and scientific data for model v erification, in order to be able to extrapolate the Megapie experience for the future ADSs

IRRADIATION

22 JUILLET 2014 CEA | 10 AVRIL 2012 | PAGE 8

Main goals :

– confirm the main operating parameters,

– obtain neutronic performances, in order to validate the neutronic codes and spallation models

– to confirm material performances evaluated during design support phase,

Aug 21 st 2006Aug 14 th 2006

MAIN RESULTS ON NEUTRONIC PERFORMANCE & GAS PRODUCTI ON

Mapping of the neutron flux in its different components (thermal, epithermal, fast) in the SINQ facility around the target. Innovative measurements inside the MEGAPIE target

Measurements complemented by corresponding calculations: code validation

Comparison with solid targets

Successful measurements of radionuclides at different irradiation times

Estimation of the release rates at the beginning of irradiation and towards the end.

Good agreement with calculations

Confirmation of results on release of Hg and Po from the design phase

No mass measurement of stable isotopes, only indirect information from pressure measurements

Xe

DECOMMISSIONING PHASE 1/2

� After the irradiation, target up to mid February 2007 in theoperating position until the decay heat has decreased toabout 300 W.

���� Controlled freezing of LBE necessary due to expansion ofsolid LBE after re-crystallization:

���� Mitigation possible if cooling rate kept as low as 0.02°C/min from solidification point to 60°C. (specific proced urefor freezing the LBE in Lower Target Enclosure)

���� Cooling circuits and gas volumes emptied, rinsed anddried,

���� Target disconnected and sealed up with blind flanges, thenstored for several months.

���� Target transferred to ZWILAG hot laboratories , using asteel container.

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Container for target transportation

DECOMMISSIONING PHASE 2/2

� Target cut with band saw (provided by Behringer) in 19 slices.

� About 8 (weight) % of the target transported to the PSI Hot labs

as samples material for PIE.

� Remaining target pieces (92%) in steel cylinder in a KC-T12 concrete container (TC2), for Storage and Disposal.

� Visual inspection of the T91 window done:

� some materials deposited in the central area of the window (mostly in aluminum window of safety hull): after removing the materials no cracks or other dam ages observed. � SEM investigations: porous structure, C, O with lit tle amount of Sifor the black material and Si, O with little C for the white material.

� US measurements on T91 window: no detectable change in the thickness of the window, (no evident dissolution/ co rrosion effects). (validation of the choice not to control the oxygen activity in the LBE).

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POST IRRADIATION EXAMINATIONS

Objectives of the PIE are to understand: - microstructural, mechanical and chemical changes

in the structural materials in the target induced b y irradiation and LBE corrosion,

- the production, distribution and release of the spallation and corrosion products in the LBE.

���� Organized effort of 8 partners of the MEGAPIE initia tive : CEA, CNRS, ENEA, FZK, JAEA, LANL-DOE, PSI and SCK.

� PIE program: mechanical tests and microstructure analyses will be performed on different components, particularly on those in the lower part of the target with high irradiation doses.

� Small specimens for the PIE cut from the pieces with an EDM machine (Electrical Discharge Machining) and a diamond disc saw in PSI’s hot cells.22 JUILLET 2014

EDM cutting machine

Samples produced by EDM machine

PIE TESTS

Specimens foreseen for mechanical tests and microstructure analyses of the target:

- TEM (Transition Electron Microscopy), - OM (Optical Microscopy),- SP (Small Punch), - Tensile and bending specimens.

���� OM specimens also used for other surface analyses such as SEM (Scanning Electron Microscopy), EPMA (Electron Probe Micro-Analysis) etc

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SEGREGATION OF LBE

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� To segregate the structural materials from the LBE a special oven has been designed and constructed by the engineering department of PSI.

���� The oven is heated with 6 heaters (0.8 kW each) built into the intermediate floor on which the target sample pieces are positioned. The lower part of the oven serves as a collector of the LBE and can be separately heated (heater band of 1.5 kW).

Before melting After melting

SAMPLE CLEANING & DECONTAMINATION

Request done by some partners: specimens: contamina tion free.

� Necessity to clean the structures to remove the LBE , in a hot-cell after melting LBE and segmenting the largepieces into smaller ones.

� Process to clean LBE:

- to sweep LBE away with tissues after heating thespecimens in oil up to about 150°C.

- to dissolve the remaining LBE on surface of sample s, two different solutions evaluated:

-1 equimolar mixture of acetic acid, hydrogen peroxi de and ethanol, (widely used for cleaning LBE on samples af ter corrosion tests)

-2 7M HNO3. ���� Option 2: could dissolve LBE much faster (at least 5 times) than 1. ���� Option 1: gas and heat production looked higher th an that in 2.

���� Cooling needed during dissolving LBE in both cases. ���� To solve the same amount of LBE, in 1 a much larger volume of the

first mixture needed, producing more contaminated e ffluent.

���� Decision to use nitric acid for the final cleaning of LBE.

TRANSPORT OF THE PIE SAMPLES

Concerning the transports of the PIE samples to the partner laboratories (CEA, JAEA, KIT, LANL, SCK-Mol):

����investigations on the transportability made, based on calculations with detailed nuclide inventories for all samples.

� Transports performed as "UN2915, Radioactive Materi al, TYPE A" transports.

� All the transports done by end of April 2013.

22 JUILLET 2014 | PAGE 16

IRRADIATION PARAMETERS

���� Necessity to determine the irradiation parameters f or all the specimens to be investigated , such as:- irradiation dose (dpa), - helium (He) and hydrogen (H) production,- proton and neutron fluences,- irradiation temperature etc

���� Except for the irradiation temperature, the remaini ng parameters can be evaluated from the final (accumulated) proton fluen ce distribution in the target by neutronic calculations.

����The irradiation temperature relies mainly on the in stant proton beam current density which is known changing greatly but, unfort unately, could not be measured during the operation of the target.

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PROTON FLUENCE DISTRIBUTION

���� To evaluate the distribution of the proton fluence a ccumulated after about four-month irradiation, gamma-mapping on the beam window of the aluminum safety-hull of the MEGAPIE target was conducted.

- Gamma-mapping performed in an area of 160x160 mm 2 in steps of 4 mm. - At each measuring position a full gamma spectrum o btained. - 22Na: the only radioactive isotope well detected, mai nly produced by the incident high energy protons. - To deduce the proton fluence distribution from the measured data, necessity to correct 22Na counts because of differences in actual measuring volume and distance at different position s on the window.

�Distribution of proton fluence obtained and available for neutronic calculations ofirradiation parameters.

� Maximum proton fluence of the MEGAPIEtarget is 1.93E +25 p/m2

22 JUILLET 2014

CFD CALCULATIONS FOR T MAPPING

� Thermal hydraulics calculations carried out with CF D model to evaluate the temperature distribution in the lower part of the target,� Comparison with temperatures measured with thermoco uples. � Some temperatures measured about 15°C higher than p redicted. � Some wrong attributed positions of the thermocouple s could explain some of the calc/exp discrepancies.� A significant difference of temperature calculated between inner side and outer side, up to 25 to 30°C at flow guide edge .

22 JUILLET 2014

T INSTABILITIES

Instabilities , particularly due the effect of the by-pass pipe, and evidencedthanks to experiments with infra-red camera, during integral tests. ���� Large Eddy Simulations (LES) carried out to analyse these instabilities, close to the window, with TRIO-U-VEF parallelized co de, to assess near the window :

- level of temperature and- velocity fluctuations ���� to give realistic data forthermo-mechanical studies aiming to demonstrate the integrity of the T91 window.

� These data also show the difficultyto attribute an average temperature of LBE, close to the window.�Nevertheless, average temperatures , taking into account the irradiation,

need to be recalculated using the heat deposition d ata from the output of the neutronic calculations.

CHEMICAL & RADIOCHEMICAL ANALYSIS OF LBE

- Decision to perform chemical and radiochemical anal yses on spallation and corrosion products in LBE , Ag-absorber, cold-trap (CGS).

- Samples taken from all slices before melting LBE ( preparation of the samples for mechanical testing).

- Size of the LBE samples determined by the total ac tivity that can be handled in the laboratories.

- Distribution of the activity within the target mate rial was not found homogeneous due to different phenomena such as deposition, tran sport during solidification and diffusion.���� For an estimation of the maximum activity we have r elied on the activation calculations: maximum activity that can be present in the LBE can be calculated assuming homogeneous distribution. ( assumption sur ely conservative, since the deposition of radioactive material lead to a decrea se of the LBE-activity: such phenomena observed in a liquid LBE target irradiate d at CERN ISOLDE).

���� at each individual sample position, pre-drilling/cu tting necessary to remove the contaminated surface, to avoid smearing of material during the sawing process and/or contamination with sawdust. | PAGE 21

RESULTS ON LBE SAMPLES 1/2

The following results from chemical characterization s have been obtained:

- γγγγ-spectrometry measurements of all specimens (withou t prior chemical separations) has been completed.

Results: 207Bi, 194Hg/Au and 173Lu distribution in the MEGAPIE target The following radio-nuclides identified by γγγγ-spectrometry: 60Co, 101Rh, 102Rh,

108mAg, 110mAg, 133Ba, 172Hf/Lu, 173Lu, 194Hg/Au, 195Au, 207Bi.

- For some of these nuclides the activities can be ea sily evaluated from γγγγ-spectrometry results (e.g. 207Bi, 194Hg/Au), while other nuclides can only be determined after chemical separations (e.g. 108mAg, 110mAg, 195Au, 129I, 36Cl and αααα-emitting 208-210Po).

- Bulk LBE contains only noble metals that have a si gnificant solubility in LBE,

| PAGE 22

RESULTS ON LBE SAMPLES 2/2

- radionuclides of elements with low solubility in L BE or sensitive to oxidation: only detected in samples taken at the LBE/steel interface and the LBE/cover gas interface ,���� accumulations on the walls increased dose rates and locally increased decay heat,

- 129I is lower than expected,

- 208-210Po homogeneously distributed � αααα activity well predicted with FLUKA and MCNPX codes.

* Filled triangles: bulk LBE samples and

* Non-filled triangle: samples from the LBE/steeland LBE/cover gas interfaces.

22 JUILLET 2014 Example of measured/modeled activity concentration of polonium ;

ALKALINE EXTRACTION

Complementary to these characterizations, studies, d edicated to the separation of spallation products from LBE, were pe rformed at PSI (with University of BERN):� Technique based on the alkaline extraction shown to be suitable for the extraction of Po from heavy liquid metals u sed in nuclear systems. � For this purpose, irradiated LBE samples from CERN ISOLDE used for model experiments. � Alkaline extraction proved to be a powerful techniq ue for the extraction of numerous radionuclides present in the irradiated liquid metal. � For the extraction of Po isotopes, maintaining reducing conditions and avoiding any ingress of moisture would guarante e their fast and reliable separation . � Such purification would decrease radiological conce rns during maintenance and shutdown of the facility.

���� Nevertheless several crucial problems to be solved before licensing such a separation method on an industrial scale :

- high corrosivity of molten hydroxides,- their hygroscopic property. 22 JUILLET 2014

CONCLUSIONS

- Target was designed by Megapie Consortium, manufactu red in France, Latvia & Switzerland (and Italy and Switzerland for ancillar y systems),

- Target operability was demonstrated during integral tests in PSI, - Irradiation was carried out end of 2006 (4 monthes) in SinQ PSI and contributed to

the validation of the models used during design pha se. - Decommissioning, and waste management phases were d efined and executed

properly by PSI. - Post Irradiation Examinations were prepared by Mega pie consortium; cutting,

sampling, cleaning, samples preparation and shippin g were performed by PSI teams. - The chemical analysis recently performed on spallat ion and corrosion products in

the LBE are very relevant for further applications of LBE as a spallation media and more generally as a coolant.

- The Megapie feedback provides to: ADS Community a unique relevant design and operatio nal feedback which will be a decisive contribution to the development of this op tion for the transmutation of minor actinides (ie MIRRHA)

- - Fast Reactor Community, Lead & LBE, a very large f eedback on materials and coolant (also for Sodium Fast Reactors: innovative option for coolant of some ancillary cooling system, material behaviour,…)

- - Neutron scattering Community, a significant feedba ck for future HLM targets.

GREAT INFORMATION!!!

The final MEGAPIE Technical Review Meeting (TRM) will be the last in a series of 11 meetings which were held on a regular basis during the project. In contrast to other TRMs the current meeting will be open to all interested researchers from the ADS, Material Science and Target Community and – of course – to all contributors to the MEGAPIE project.

In this TRM the main achievements of the MEGAPIE project in the past 15 years will be reviewed and – in a combined session with IWSMT – the latest Post Irradiation Examination (PIE) results will be presented for the first time.

Moreover, one session will be devoted to current ADS projects .

The final MEGAPIE TRM will be held in Bregenz, Austria , subsequent to the 12th

International Workshop on Spallation Material Technology (IWSMT-12), from October 23 – 24, 2014 .

Website: https://indico.psi.ch/conferenceDisplay.py?confId=3182 | PAGE 26

ACKNOWLEDGMENTS

The authors would like to thank warmly:

- the 9 members of MEGAPIE Consortium,

- all contributors to the MEGAPIE project, & more particularly:

- the PSI team for its constant dedication,

- the European Commission for previous support ( Program MEGAPIE Test and GETMAT ( to support the European partners for the PIE of structural materials).

22 JUILLET 2014 | PAGE 27

French Atomic & Alternative Energies Commission Nuclear Energy DirectorateNuclear Technolohy Department

Commissariat à l’énergie atomique et aux énergies alternatives

Centre de Cadarache | DEN/CAD/DTN Bâtiment 710

13108 Saint-Paul-Lez-Durance

T. +33 (0)4 42 25 44 71 | F. +33 (0)4 42 25 78 78

Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 01922 JUILLET 2014

CEA | 10 AVRIL 2012

On behalf of MEGAPIE Consortium and Paul Scherrer Institute

Thank you for your kind attention !